FIG. 9 of EP2292444 A2 discloses a transport device comprising a transport duct, by means of which book blocks are conveyed to a finishing station. A feed element in the form of a paddle wheel receives the fed book blocks individually in intermediate spaces between racks arranged on a disc, and initially conveys them onwards in the same rotational plane through rotation of the paddle wheel. After a predetermined angle of rotation, the book block is ejected from the feed element in a recess of the transport duct into said duct, transferred and passed on. The aforementioned construction of the feed element is accordingly configured such that the book blocks can be present in the transport duct, in which they are to be conveyed onwards, at any desired angle to the transport duct from vertical to horizontal. As a result of the construction of the aforementioned transport device, the feed element can merely be rotated in a single direction, the book blocks being able to fall apart and fan out in the relatively large radially formed intermediate spaces between the racks during the rotational movement. Here, there is the risk that the book blocks may be damaged when fanning out. This can greatly limit the transport speed of the books. As a result of the paddle-wheel-like feed element with a disc which is delimited on one side, it is also not possible to operate a plurality of handover devices on the same transport duct.
In a further embodiment from this specification, shown in FIG. 1, book blocks are initially conveyed into the transport duct using feed elements, in the form of racks, of a feed device. Here, they are received by transport fingers of the transport device and conveyed away along the transport duct. Since the feed elements have a speed component counter to the conveying direction of the transport duct when the book blocks are deposited, and the book blocks are received by the transport fingers at the deposition time, the speed difference between the book block and the transport finger increases. In particular at relatively high operating speeds, this increases the risk of the book blocks falling apart or the individual printed sheets disadvantageously shifting with respect to one another. When a book block is handed over to the transport device, the respective feed device is arranged above the transport duct, meaning that the book block has to overcome a height difference from the transport duct when deposited by the transport finger, increasing the risk of falling apart or shifting. In addition, this feed device is found to be relatively complex, high-maintenance and expensive.